Improvement in reciprocating essigifmes



' l ZSheetszuShet. S. D; TILLMAN.

Improvement in Reciproating-Engines.

N0. 129,694, PatentedJuIyZSJN SAMEL D. TILLMAN, OF JERSEY CITY, NEWJERSEY.

IMPROVEMENT IN RECIPROCATING ENGINES.

Specification forming part of Letters Patent No.l IQQJSQ, dated July 23,125.72.

Specification describing an Improvement in Steam Engines, applicable,also, to pumps where a reciprocating is connected with a rotatorymotion, invented by SAMUEL D. TILL- MAN, of Jersey City, inthe State ofNew J ersey.

The invention is intended for small engines and-pumps, where thefriction, when the parts are `fitted with sufficient tightness to makepermanent and practical work, becomes a very important element.

Irwill confine myself, mainly, to describing the steam-engine. It willbe understood that in air or gas engines, pumps, and probably otherapparatus, the saine construction may be employed and the sameadvantages may be realized. A certain amount of pressure is necessary tomaintain a proper tightness of fit between the piston and the interiorof the cylinder. This involves friction, and with any ordinary packingit involves a yconsiderable resistance from this cause. Inv proportionas y the engine is enlarged the friction becomes of I less and lessimportance; but in reducing the size of the engineit is possible toattain such a reduction that the friction will prevent its workingunless correspondingly reduced by the introduction of delicacies in theadjustment which would require a constant attention.

The object of this invention iswto allow the packing to be setup withordinary force, and to wear for an ordinary periodiorlonger, ifpossible, than usual, and yet to render practicable the employment ofengines of very small power and requiring a correspondingly smallconsumption of steam. As one fundamental step toward the attainment ofthis end, I increase the proportion of the diameter to the length of thecylinder. I give a very large area to the piston, with a very shortstroke, and multiply the motionrby means of an unequal beam. The laws bywhich the resistance due to the friction is thus lessened are too wellknown-to require elueidation. A small piston, traversing in a longcylinder like a' gun-barrel, involves very much more frictionyal rubbingof the piston and cylinder than one of corresponding volume contractedin length and expanded in diameter, like a blackingbox. It is easyinpractice to efficiently clothe the extended cylinder-ends and preventloss of heat. So far as yet described my invention involves only anexaggeration of proportions which have been before approximated to. l Ihave rendered a very great exaggeration practicable and highlybeneficial by certain features of construction which I have applied incombination. These features have been known before in other and dierentcombinations.

I connect the extended piston to the short arm of the beam by wideknuckle-j oints, which allow the employment of small pins, and involvebut slight friction in transmitting the relatively great force employed,'and I mount the unequally-divided beam on knife-edges, s0 arranged thatthe strain in both directions is received on bearings which involve nofriction and little necessity for lubrication or attention. p

The following is a description of what I consider the best means ofcarrying out the invention.

The accompanying drawingforms a part of this specification.

Figure l isa central vertical section through the cylinder and piston,and also through a part of the beam near the central line, with anelevation of the crank and the other parts.

Fig. l2h is an additional view of the connect-` in g-link between thepiston-rod and the beam. It will be understood that any ordinary meansnot represented`may be employed for guiding the cross-head or upperendlof the piston-rod.

Fig. 2 is a perspective view, on a larger scale, of certain portions ofthe mechanism detached.V

Similar letters of reference indicate like parts in both the gures. 1

Figs. 3 Vand A are merely graphic illustrations. They representperspective views of halves of two cylinders of equal capacity, one ofwhich is short and of the proper proportion for my invention, andtheother is of the ordinary proportions for ordinary steam-engines.

It will be seen, from the construction and arrangement of the valvesandpassages, how the device-may, with obvious modiiications oradditions, be used as a steam-engine, or, with no additions, be usedas apump. In describing it as a steam-engine it will be necessary toconceive of the addition of some ordinary mechanism for controlling thevalves.

A is a short cylinder of large diameter, with swelled top and bottom,which may be thickly clothed on all sides to retain heat; and A' is abed-plate, which supports all the parts. B is a strong, stiff piston, ofsuch thickness as to leave room for but a short stroke. The pis ton-rodb is connected, by a wide knuckle-j oint of many knuckles and a pin ofsmall diameter, to a Wide flat link, F, which is, in turn, connected, bya corresponding knuckle-joint, f, to the short arm of an unequal beam,D, the other end of which bea-m is connected, as usual, to aconnecting-rod, Gr, which gives motion to a crank, H, of large throw,fixed on the mam shaft I, which gives motion to the mechanism, and alsothrough ordinary connections-'not represented to the valves of theengine, which may be of any ordinary or suitable character. These valvesare represented here as simple hinged flaps, shutting onto inclinedperforated seats. They may be worked by arms attached to the projectingends of their shafts. The uprights A2 of the framing support the doubleknife-ed ges, which carry the main center of the unequal beam D. Theseknife-ed ges are peculiar. The beam is cast in a single piece, of suchthickness as to be almost perfectly rigid. Two knife-edges, Z1 cl2,formed thereon at each side, rest in corresponding supports on theuprights A2, adapted to allow the proper rocking motion withoutfriction. A wide space in between, exactly in line with theseknifeedges, is recessed, as indicated, and receives a knife-edge, e,which is cast on the rigid binder E, which goes over the whole, and issecured by bolts, not represented. The beam D and theI binder E may becast with deep webs to make them very rigid. The uprights A2 of theframing are connected by a transverse piece, sothat the whole frame isas stiff as possible.

When, in the workin g of the machine, steam is admitted below the pistonB the strain is thrown on the binder E, and as the crank H turns underthe force transmitted the beam D rocks upon the knifeedge e. When, bythe action of the valves, the steam is discharged below the piston andis admitted above, the strain due to the pressure on so large an area isreceived on the lower knife-edges d1 cl2, and the beam D rocks thereon,in both cases without friction. It will be understood that theknife-edges must be adjusted exactly in line with each other. Theknuckle-joints f1 f2 being duplicated and extended widely, with narrowknuckles, as represented, allow the employment of so small a pin, onwhich the action turns, that the friction at these points involved inthe transmission of a great force is very slight. The friction of a pinbeing` as its diameter, by making the 'pin of great length,

comparatively, and supporting it at frequent intervals, as in thisdevice, the friction of the pin is reduced to a minimum.

The law by which the saving' in the loss by friction is governed is verysimple, and it may be proper to lay it down here. The friction of apiston and cylinder, other things being equal, varies directly as thediameter of the cylinder. The capacity, and consequently the power,other things being equal, varies by a very different ratio, and is asthe areaof the pistonthat is, as the square of its diameter. Hence, byincreasing the diameter of a given piston and cylinder tenfold the forceof the steam thereon becomes one hundred times greater, while thefriction is onlyten times greater than before; or, in other words, thefriction is relatively to the power only one-tenth as great as before.This fact has long been known to many, and perhaps to most, engineers;but until my invention it has been incapable of utilization by reason ofthe great loss in the friction in the joints in the connections by whichthe motion is communicated. My invention allows the connections to bealmost frictionless. and multiplies the small motion of the piston B,and makes it available on a light crank with large throw, so as to serveefficiently for very small engines and supply a want long felt and neveryet fully met.

I claim as my invention- 1. The combination of the following ele` ments:The cylinder A, and piston B of large diameter and short stroke, theunequal beam D, receiving the force from the piston on the short arm,the knife-edges d1 d2 to allow the motion of the beam D in one directionon a frictionless fulcrum, and the knife-edge e in a line with theknife-edges d1 cl2 to allow the motion in the opposite direction, bot-l1motions being thus on nearly-frictionless fulcruins, all operatingtogether as specified.

2. I also claim, in combination with the pis ton B of large diameter andshort stroke and unequal beam D, the wide series of knuckles f of smalldiameter, adapted to support, by means of a pin of small diameter, agreat force with little friction, as specified.

In testimony whereof I have hereunto set my hand in presence of twosubscribing wit nesses.

SAMUEL D. TILLMA N.

Witnesses A. HOERMANN, C. G. LIVINGs.

